Sports boards are popular and widely known for providing recreational entertainment in both warm and cold weather environments. Sports boards are often composed of a lightweight foam core, plastic film skins on the top and the side rails, and a thick slick plastic bottom surface layer. Typically a polyethylene foam core is used and the skins and slick layers are made of composites of solid polyethylene sheet material and foam polyethylene material. Use of polyethylene for both the core and skins allows for heat laminating, bonding the skins to the core of the board because of the thermoplastic properties of both polyethylene foam and solid polyethylene sheet material.
One drawback to using a polyethylene core is that it does not have the structural stiffness that other foam polymer materials may have at similar densities. For example, expanded polystyrene (EPS) foam has more structural stiffness at a similar density than does polyethylene (PE) foam. A stiffer core for the sports board improves the sports board performance in a variety of applications, such as surfing, sledding, or similar activities.
One problem with using polystyrene cores is that polyethylene or other polyolefin skins are difficult to bond directly to polystyrene. Typically, a solvent-based adhesive will have to be used to bond a polyolefin to polystyrene. Solvent-based adhesives have several drawbacks. Solvent-based adhesives outgas the solvents as they cure. In some cases, if the adhesive cures incompletely, then it does not achieve the desired bonding strength.
It may be desirable to develop a method of heat bonding a polyolefin material to an expanded polystyrene foam material to form a sports board that has the structural stiffness advantages of a expanded polystyrene core and the desirable tactile properties of polyolefin skins bonded to the core.